Invertebrates

Question 1

which phylum represents the basal Metazoan?

Answer 1

Porifera

Question 2

Phylum Porifera

Answer 2

• “to have pores” - sponges

- least complex animals (MC, differentiated cells, and no symmetry, tissues or organs)

Question 3

Simple Sponge Morphology

Answer 3

osculum: open end
spongocoel: central cavity
NOT a digestive cavity - digestion is intracellular

Question 4

what is the SDT for Porifera?

Answer 4

choanocytes

• “Collar cells” - feeding cells of sponges
• Very similar to choanoflagellates
• Flagellated
• Collar of microvilli
• Line spongocoel
• Ingest bacteria, food particles

Question 5

what phylum represents the basal Eumetazoa?

Answer 5

Phylum Cnidaria

Question 6

what are the Eumetazoan SDTs?

Answer 6

• true tissues
• radial symmetry
• diploblastic

Question 7

what are the SDTs for Cnidaria?

Answer 7

Cnidocytes

• Specialized stinging cells
• Thin (2 layers), gastrovascular activity
• Mostly marine

Question 8

what is so special about protostomes?

Answer 8

• diverse, paraphyletic group
• must have ancestral (protostome) development traits
• some have derived (deuterostome) development

Question 9

is Deuterostome a mono-, para-, or polyphyletic group? why?

Answer 9

Mono because all have derived development traits

Question 10

what are ancestral traits for Lophotrochozoan?

Answer 10

from bilateria ancestor

• bilateral symmetry
• triploblastic
• protostome development (some have deutero. pattern)

Question 11

what is the SDT for Platyhelminthes?

Answer 11

Acoelomates

Question 12

Describe Platyhelminthes

Answer 12

• Dorsoventrally flattened

- Can be free-living or parasitic

Question 13

describe Rotifera

Answer 13

• freshwater/marine, damp soil

- Very small

Question 14

what are the SDTs for Rotifera?

Answer 14

• Corona: crown of cilia at anterior end

- Pseudocoelomate

Question 15

what are the 3 main body parts/SDTs for Mollusca

Answer 15

• mantle: thin sheet of tissues covering visceral mass (often secretes CaCO3)
• visceral mass: main body mass, contains viscera (internal organs)
• foot: structure for locomotion

Question 16

Radula

Answer 16

• Present in many mollusks
• Belt of teeth in mouth area
• Scrapes up food
• Absent from bivalves

Question 17

describe Annelida

Answer 17

• Little rings
• Repeated segmentation
• Body wall, coelum, many organs
• Marine, freshwater, soil

Question 18

what are the SDT for Nematoda?

Answer 18

• Body covered in cuticle

- pseudocoelomates

Question 19

describe Nematoda

Answer 19

• Roundworms
• Aquatic, soil, parasitic
• Heartworms, trichinosis

Question 20

what is the SDT for Arthropoda?

Answer 20

jointed Appendages:

-Often modified for motility, feeding, sensory info
-Exoskeleton (Covers entire body- jointed,
Made of chitin and protein)

Question 21

describe Arthopoda

Answer 21

-Joint foot
-Largest phylum
-Often have deuterostome development traits
-Arthropod Structure:
Segmented bodies
Often 3 parts: head, thorax (legs and wings), abdomen